VERY well before 2500 BC, God's second, most impressive, amazing, and gracious miracle-plan began. His first was the 6 days of Creation. The second was the fact that He would need to have something or someone that would have to pay for the mistakes that mankind made beginning in Genesis 3:6.
Throughout the Bible, sacrifices had to be made to pay for the mistakes. After several thousands of years and many, many prophecies, God's miracle-plan was to be born. Yes, we already celebrated Jesus' birthday, but this is how awe-inspiring and real this is!
As His Creation was beginning to discover their home, an estimated 5,000-10,000 years before Christ's birth, Satan tempted Eve to disobey her Creator - and she did. Later, Eve tempted Adam to disobey his Creator - and he did. Instead of God completely destroying His Creation, eradicating everything He had made, He chose mercy and grace.
God loved and continues to love us that much.